JP2002365118A - Mechanical type temperature and pressure corrector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical type temperature and pressure corrector provided with a cleaner applying constant contact pressure onto a disc all the time. SOLUTION: This corrector is provided with the pressure correcting disc 36 rotating interlocked with a gas meter, a pressure correcting ring 38 moving along a radial direction of the disc 36 by a displacement proportional to pressure from a pressure sensor for sensing pressure of gas to be continuously speed- variable, a temperature correcting disc 53 for transmitting the rotation to a correction integrating counter 64, a temperature correcting disc 55 for interlocking with the pressure correcting ring 38 to transmit the rotation to the temperature correcting disc 53, and moving along a radial direction of the disc 53 by a displacement proportional to a temperature from a temperature sensor for sensing the temperature of the gas to be continuously speed-variable, and the cleaners 70 provided opposedly to surfaces of the pressure correcting disc 36 and the temperature correcting disc 53 respectively, and having respectively wiping members 77 for contacting with the surfaces of the discs 36, 53 by their dead weights to clean the surfaces of the discs 36, 53.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical temperature and pressure compensator provided in a gas meter for measuring a flow rate of a gas, performing compensation in accordance with a change in gas temperature and pressure, and integrating and displaying the result on a compensation integrating counter. .

[0002]

2. Description of the Related Art Since the volume of a gas changes depending on the pressure and temperature, the volume of the gas passing through the gas meter changes depending on the operating pressure and operating temperature of the gas. Therefore, in order for the gas meter to accurately measure the gas flow rate, it is necessary to correct the gas flow rate and the gas use temperature, and to display the corrected integrated flow rate on the corrected integration counter.

Therefore, conventionally, a mechanical temperature and pressure compensator (TPCK) is provided in a gas meter to automatically and continuously perform compensation in accordance with a change in temperature and pressure of a gas, so that a gas at a working temperature and a working pressure is used. The volume is converted to a volume at a reference temperature and a reference pressure.

In general, a liquid inflatable Bourdon tube method is used for a temperature sensor to perform high-precision temperature correction. A pressure sensor generally uses a Velofram method to perform high-precision pressure correction. Then, the mechanical operation of the temperature sensor and the pressure sensor is transmitted to the correction device to perform the correction.

FIG. 3 shows a conventional mechanical temperature and pressure compensator, in which a lower frame 1 is provided with a rotating shaft 3 via a bearing 2.
Are supported rotatably in the vertical direction. A disk 4 made of a metal material such as stainless steel is fixed to the upper end of the rotating shaft 3 so as to rotate about the rotating shaft 3 as an axis.

A pressure correction ring 5 and a temperature correction ring 6 are arranged symmetrically on the upper surface of the disk 4 with the rotation center of the disk 4 interposed therebetween, and the pressure correction ring 5 and the temperature correction ring 6 are respectively provided on the outer peripheral surface. The rotary cylinders 7, 8 having spline grooves 7a, 8a are fixed to one end faces of the rotary cylinders 7, 8.

The rotary cylinder 7 is rotatably supported by a support member 9, and the support member 9 is connected to a responsive member 10 that responds to a mechanical operation from a pressure sensor (not shown) of a bellofram type. .

The rotary cylinder 8 is rotatably supported by a support member 11. The support member 11 includes a response member 12 which responds to a mechanical operation from a liquid expansion type Bourdon tube type temperature sensor (not shown). Are linked.

Therefore, the rotary cylinder 7 provided with the pressure correction ring 5 is movable in the radial direction of the disk 4 by the movement of the response member 10 in the direction of the arrow, and the rotary cylinder 8 provided with the temperature correction ring 6 is The disk 4 can be moved in the radial direction by moving in the direction of the arrow 12.

Pins 5a and 6a are protrudingly provided at the center of rotation of the pressure correction ring 5 and the temperature correction ring 6. These pins 5a and 6a are connected to the other end of a biasing spring 14 having one end fixed to the upper frame 13. The pressure correction ring 5 and the temperature correction ring 6 are in contact with the upper surface of the disk 4 with an appropriate pressing force via the pins 5a and 6a by the urging force of the urging spring 14.

Accordingly, the rotation of the pressure correction ring 5 is transmitted to the disk 4 by frictional force, and the rotation of the disk 4 is transmitted to the temperature correction ring 6 by frictional force.
When the pressure correction ring 5 and the temperature correction ring 6 are independently moved in the radial direction of the disk 4 by the response members 10 and 12, the peripheral speed changes, so that the speed is continuously variable and the rotational speed is increased or decreased. Has become.

On the other hand, the rotational force caused by the gas passing through the gas meter is applied to the first transmission shaft 1 via the clutch 16.
The rotation of the transmission shaft 17 is transmitted to the non-correction integration counter 19 via the first bevel gear mechanism 18.
It is linked to.

A first spur gear 20 is provided in the middle of the first transmission shaft 17, and the first spur gear 20 is transmitted to a second transmission shaft 22 via a reduction gear train 21. The second transmission shaft 22 is connected to the third transmission shaft 2 via a second bevel gear mechanism 23.
4 has been transmitted. Further, a second spur gear 25 is provided on the third transmission shaft 24, and the second spur gear 25 meshes with the spline groove 7 a of the rotary cylinder 7.

Therefore, the rotation of the gas meter is transmitted to the non-correction integrating counter 19, and is also decelerated and transmitted to the pressure correction ring 5, so that the rotation of the pressure correction ring 5 causes the disk 4 to rotate.

A third spur gear 27 provided at one end of a fourth transmission shaft 26 meshes with a spline groove 8a of the rotary cylinder 8 of the temperature correction ring 6. In addition, the fourth
The other end of the transmission shaft 26 is linked to a correction integration counter 29 via a transmission gear train 28. Accordingly, the pressure-compensated and temperature-compensated rotation is transmitted to the compensation accumulation counter 29, and the volume at the working temperature and working pressure is converted into the volume at the reference temperature and pressure and integrated and displayed.

Further, as shown in FIGS. 4 and 5, a cleaner 30 for cleaning the surface of the disk 4 is provided opposite to the surface of the disk 4. The cleaner 30 removes abrasion powder and dust generated by friction between the disk 4 and the pressure correction ring 5 and the temperature correction ring 6 and adheres to the surface of the disk 4, and is fixed to the frame 1. A resilient wiping member 32 such as a sponge or a felt cloth is attached to the lower surface of the tip of the attachment piece 31. The wiping member 32 comes into contact with the surface of the rotating disk 4 and removes abrasion powder and dust adhering to the surface of the disk 4.

[0017]

However, the cleaner 30 in the conventional mechanical temperature and pressure compensator has a structure in which the wiping member 32 is fixed to the bracket 31. At the beginning of the assembly, the cleaner 30 has a suitable structure with respect to the surface of the disk 4. Although the contact pressure is high, the wiping member 32 always slides on the disk 4, so that the wiping member 32 gradually wears, and the contact pressure decreases, and the function of removing abrasion powder and dust decreases. Therefore, there is a problem that the wiping member 32 needs to be periodically replaced, which leads to a high maintenance cost.

The present invention has been made in view of the above circumstances, and has as its object to maintain the contact pressure of the wiping member against the surface of the disk constant for a long period of time, and to stably clean the disk for a long period of time. An object of the present invention is to provide a mechanical temperature and pressure compensator capable of reducing maintenance costs.

[0019]

According to the present invention, in order to achieve the above-mentioned object, a first aspect of the present invention comprises a rotatable disk,
The disk moves in the radial direction by a displacement amount proportional to the pressure from a pressure sensor that senses the pressure of the gas to be measured while rotating in conjunction with the rotation from the gas meter that measures the flow rate of the gas, and the surface of the disk A pressure compensation ring that transmits rotation in a stepless manner by contacting it, and a displacement proportional to the temperature from a temperature sensor that senses the temperature of the gas to be measured while rotating in contact with the surface of the pressure-compensated disk A temperature correction ring that moves in the radial direction of the disk and the rotation is transmitted steplessly, and a correction integration counter that integrates and displays the gas flow rate in conjunction with the rotation of the temperature correction ring that has been subjected to pressure correction and temperature correction. A wiping member that is provided slidably in the vertical direction in opposition to the surface of the disk and has elasticity to contact the surface of the disk by its own weight and clean the surface of the disk. In mechanical temperature pressure compensation apparatus characterized by comprising a cleaner having the end.

A second aspect of the present invention is a pressure compensation disk which rotates in conjunction with rotation from a gas meter for measuring a gas flow rate, and a pressure sensor which interlocks with the pressure compensation disk and senses the pressure of the gas to be measured. A pressure compensating ring that moves in the radial direction of the pressure compensating disc by a displacement amount proportional to the pressure and is continuously variable, a temperature compensating disc that transmits rotation to a compensation accumulating counter that accumulates and displays the gas flow rate, The temperature compensating ring is rotated by the rotation of the compensated pressure compensating ring to transmit the rotation to the temperature compensating disk, and the temperature compensating circle is displaced in proportion to the temperature from a temperature sensor for sensing the temperature of the gas to be measured. A temperature correction ring that is moved in the radial direction of the plate and is continuously variable; It is, in the mechanical temperature pressure compensation apparatus characterized by comprising a cleaner having a tip portion the wiping member having elasticity to clean the surface of the disc in contact with the surface of the disc by its own weight.

According to a third aspect, the wiping member according to the first or second aspect is a sponge or a felt cloth.

According to the above configuration, the resilient wiping member at the tip of the cleaner that comes into contact with the surface of the rotating disk can remove wear powder and dust adhering to the surface of the disk.
Further, even if the wiping member is worn, the cleaner is lowered by its own weight as the wear progresses, so that a constant contact pressure is always applied to the disk, and the exclusion function can be maintained.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment, in which a cleaner of the present invention is provided in a conventional mechanical temperature and pressure compensator, and FIG. 1 (a) excludes a pressure compensation ring 5 and a temperature compensation ring 6. FIG. 3B is a side view of the cleaner in the state, and FIG.

Referring to FIG. 1, a description will be given of a cleaner 70 for cleaning the disk 4. Two support shafts 71 and 72 vertically separated from each other are installed on the upper part of the disk 4 in a horizontal state. A cleaner body 73 is slidably supported on the support shafts 71 and 72 in the vertical direction. That is, the cleaner main body 73 is, for example, bent into a metal plate and has a U-shape including a back plate 73a and left and right side plates 73c and 73d. Notch 74
And a vertically long slot 75 that fits with the lower support shaft 72 is provided in the middle part. Therefore, the cleaner main body 73 is slidable in the vertical direction within the range of the play in the vertical direction between the long hole 75 and the support shaft 72.

At the lower end of the cleaner body 73, a caulking piece 7 is provided.
6 are integrally provided, and a resilient wiping member 77 such as a sponge or a felt cloth is fixed by caulking with its lower end protruding downward. The wiping member 77 is formed wide on the surface of the disk 4 in the radial direction of the disk 4 so as to contact at least the track width with which the pressure correction ring 5 and the temperature correction ring 6 contact.

In the cleaner 70 thus configured, since the cleaner body 73 is slidably supported in the vertical direction, the wiping member 77 is placed on the surface of the disk 4 by the weight of the cleaner body 73 including the wiping member 77. In contact.
Therefore, even if abrasion powder or dust generated by the contact between the rotating disk 4 and the pressure correction ring 5, the temperature correction ring 6 or the like adheres to the disk 4, it can be removed by the wiping member 77.

Further, the wiping member 77 is gradually worn by friction with the surface of the disk 4, but the cleaner body 73 is lowered by its own weight as the wear progresses. 77 is always a constant contact pressure,
The function of removing abrasion powder and dust can be maintained for a long time.

FIG. 2 shows a second embodiment, in which the same components as those in the first embodiment have the same reference numerals and description thereof will be omitted. FIG. 2 shows a mechanical temperature and pressure compensating device, which comprises a pressure compensating mechanism 31 and a temperature compensating mechanism 32.
First, the pressure compensating mechanism 31 will be described. The bearings 34 are attached to the vertically separated frames 33a and 33b.
The rotating shaft 35 is supported rotatably in the vertical direction via a and 34b. A pressure compensation disk 36 made of a metal material such as stainless steel is fixed to the upper end of the rotating shaft 35, for example.
The rotation is performed about the rotation shaft 35 as an axis. Further, between the frames 33a and 33b, there is provided an urging spring 37 which is wound around the rotating shaft 35 and urges the pressure correction disk 36 upward.

A pressure correction ring 38 is provided in contact with the upper surface of the pressure correction disk 36. That is, since the pressure compensation disk 36 is urged upward by the urging spring 37, the upper surface of the pressure compensation disk 36 and the pressure compensation ring 38
Is in contact with an appropriate contact pressure, so that the rotation of the pressure correction disk 36 is transmitted to the pressure correction ring 38.

The pressure correction ring 38 is fixed to one end surface of a rotary cylinder 39 having a spline groove 39a on the outer peripheral surface. The rotary cylinder 39 is rotatably supported by a support member 40, and the support member 40 is connected to a response member 41 which responds to a mechanical operation from a pressure sensor (not shown) of a bellofram type. The rotary cylinder 39 provided with the pressure correction ring 38 is movable in the radial direction of the pressure correction disk 36 by the movement of the response member 41 in the directions of arrows a and b.

On the other hand, the rotational force caused by the gas passing through the gas meter is applied to the first transmission shaft 4 via the clutch 43.
The rotation of the first transmission shaft 44 is transmitted through the bevel gear mechanism 45 to the non-correction integration counter 46.
It is linked to.

A first spur gear 47 is provided in the middle of the first transmission shaft 44. The first spur gear 47 meshes with a second spur gear 49 of the rotary shaft 35 via a reduction gear train 48. are doing. Therefore, the rotation of the gas meter is not corrected
The rotation is transmitted to the pressure correcting disc 36 while being transmitted to the pressure correction disc 36 while being reduced by the reduction gear train 48.

A cleaner 70 having the same structure as in the first embodiment is provided above the pressure compensating disk 36 so as to face the surface thereof. The wiping member 77 is in contact with at least the track width with which the pressure correction ring 38 contacts on the surface of the pressure correction disk 36.

Therefore, even if abrasion powder or dust generated by the contact between the rotating pressure compensation disc 36 and the pressure compensation ring 38 adheres to the pressure compensation disc 36, it can be removed by the wiping member 77.

The wiping member 77 gradually wears due to friction with the surface of the pressure compensating disk 36, but the cleaner body 73 descends by its own weight as the wear progresses.
The wiping member 77 always has a constant contact pressure with the surface of the pressure compensation disc 36, and the function of removing abrasion powder and dust can be maintained for a long time.

Next, the temperature compensating mechanism 32 will be described. A rotating shaft 52 is rotatably supported in the vertical direction by bearings 51a, 51b on frames 50a, 50b vertically separated from each other. A temperature correction disk 53 made of a metal material such as stainless steel is fixed to the upper end of the rotating shaft 52, and rotates around the rotating shaft 52 as an axis. Further, between the frames 50a and 50b, an urging spring 54 wound around the rotating shaft 52 and urging the temperature correction disk 53 upward is provided.

A temperature correction ring 55 is provided in contact with the upper surface of the temperature correction disk 53. That is, since the temperature correction disk 53 is urged upward by the urging spring 54, the upper surface of the temperature correction disk 53 and the temperature correction ring 55
Are in contact with an appropriate contact pressure, and the rotation of the temperature correction disk 53 is transmitted to the temperature correction ring 55.

The temperature correction ring 55 is fixed to one end of a rotary cylinder 56 having a spline groove 56a on the outer peripheral surface. The rotary cylinder 56 is rotatably supported by a support member 57. The support member 57 is connected to a response member 58 that responds to a mechanical operation from a liquid inflatable Bourdon tube type temperature sensor (not shown). I have. The rotary cylinder 56 provided with the temperature correction ring 55 is movable in the radial direction of the temperature correction disk 53 by moving the response member 58 in the directions of arrows c and d.

A cleaner 70 having the same structure as that of the first embodiment is provided on the upper part of the temperature correction disk 53 so as to face the surface thereof.
Is provided. The wiping member 77 is in contact with at least the track width with which the temperature correction ring 55 contacts on the surface of the temperature correction disk 53.

Therefore, even if abrasion powder and dust generated by the contact between the rotating temperature correction disk 53 and the temperature correction ring 55 adhere to the temperature correction disk 53, they can be removed by the wiping member 77.

The wiping member 77 is gradually worn by friction with the surface of the temperature compensation disk 53, but the cleaner body 73 is lowered by its own weight as the wear progresses.
The wiping member 77 always has a constant contact pressure against the surface of the temperature correction disk 53, and the function of removing abrasion powder and dust can be maintained for a long time.

Further, an interlocking gear train 59 is interlocked between the rotary cylinders 39 and 56 of the pressure correction mechanism 31 and the temperature correction mechanism 32. That is, a spur gear 61 meshing with the spline groove 39a of the rotary cylinder 39 is provided at one end of the transmission shaft 60.
And a spline groove 56 of the rotary cylinder 56 is provided at the other end.
A spur gear 62 meshing with a is provided.

The lower end of the rotating shaft 52 of the temperature correction mechanism 32 is provided with a correction integration counter 6 via a bevel gear mechanism 63.
It is linked to 4. Therefore, the pressure-compensated and temperature-compensated rotation is transmitted to the compensation accumulation counter 64, and the volume at the operating temperature and pressure is converted to the volume at the reference temperature and pressure, and the accumulated value is displayed.

Next, the operation of the mechanical temperature and pressure compensator will be described.

The rotation force of the gas passing through the gas meter is transmitted to a first transmission shaft 44 via a clutch 43, and the rotation of the first transmission shaft 44 is transmitted via a bevel gear mechanism 45 to a non-corrected integration counter 46. And at the same time, to the rotating shaft 35 via the reduction gear train 48.

Therefore, since the pressure compensating disk 36 rotates about the rotation shaft 35 as an axis, the pressure compensating ring 38 in contact with the upper surface of the pressure compensating disk 36 is rotated by frictional force. Is transmitted to the temperature correction ring 55 via the interlocking gear train 59 meshing with the spline groove 39a of the rotary cylinder 39. Since the temperature correction ring 55 is in contact with the upper surface of the temperature correction disk 53, the temperature correction disk 53 is rotated by the frictional force, and the rotating shaft 52 rotates integrally. The rotation of the rotation shaft 52 is linked with the correction accumulation counter 64 via the bevel gear mechanism 63.

In this state, the pressure of the gas is sensed by a bellofram type pressure sensor (not shown), and the temperature of the gas is sensed by a liquid expansion type Bourdon tube type temperature sensor (not shown).

The pressure sensor of the bellofram type senses the pressure, and when the pressure is high, the responsive member 41 responding to the mechanical operation moves in the direction of the arrow a and the pressure compensating ring 38
Moves in the outer peripheral direction of the pressure correction disk 36, and when the pressure is low, the responsive member 41 moves in the direction of arrow b, and the pressure correction ring 38 moves in the inner peripheral direction of the pressure correction disk 36. That is, when the gas pressure is high, the pressure correction ring 38 contacts the outer peripheral portion of the pressure correction disk 36 to increase the speed, and when the gas pressure is low, the inner peripheral portion of the pressure correction disk 36 is increased. The pressure correction ring 38 comes into contact with the gas to decelerate, and correction according to the gas pressure is performed.

A liquid inflatable Bourdon tube type temperature sensor senses the temperature of the gas, and when the temperature is high, a response member 58 which responds to a mechanical operation moves in the direction of arrow c so that a temperature correction ring 55 is provided. Moves in the outer peripheral direction of the temperature correction disk 53, and when the temperature is low, the response member 58 moves in the direction of arrow d, and the temperature correction ring 55 moves in the inner peripheral direction of the temperature correction disk 53. In other words, when the gas temperature is high,
The temperature correction ring 55 is brought into contact with the outer peripheral portion of the temperature correction disk 53 to be decelerated.
The temperature correction ring 55 is brought into contact with the inner peripheral portion of 3 to increase the speed, and the correction according to the gas temperature is performed.

Therefore, the rotation of which the pressure and temperature have been corrected is transmitted to the temperature correction disk 53, and the rotation thereof is linked to the correction and accumulation counter 64. The information is transmitted, and the volume at the operating temperature and the operating pressure is converted into the volume at the reference temperature and the operating pressure, and is integrated and displayed.

As described above, the pressure-compensated and temperature-compensated rotations are transmitted to the pressure compensating mechanism 31 and the temperature compensating mechanism 32, and the volume at the operating temperature and pressure is converted into the volume at the reference temperature and pressure. Then, during the integrated display, even if abrasion powder or dust adheres to the surfaces of the rotating pressure correction disk 36 and temperature correction disk 53, they can be eliminated by the wiping member 77.

The wiping member 77 gradually wears due to friction with the surfaces of the pressure correction disk 36 and the temperature correction disk 53, but the cleaner body 73 descends due to its own weight as the wear progresses. The wiping member 77 always has a constant contact pressure with respect to the surfaces of the disk 36 and the temperature correction disk 53, so that the function of removing abrasion powder and dust can be maintained for a long time.

[0054]

As described above, according to the present invention, a cleaner body having a resilient wiping member at the tip end is provided.
Provided slidably in the vertical direction facing the surface of the disk,
The cleaner body contacts the surface of the disk by its own weight to clean the surface of the disk.

Therefore, the abrasion powder and dust adhering to the surface of the rotating disk can be removed by the wiping member, and even if the wiping member is worn, the cleaner descends by its own weight as the wear progresses. There is an effect that the contact pressure is always constant against the plate, the exclusion function is maintained for a long time, and the maintenance cost can be reduced.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a mechanical temperature and pressure compensator of the present invention, wherein (a) is a side view of a cleaner without a pressure compensating ring and a temperature compensating ring, and (b) is a front view thereof. .

FIG. 2 is a configuration diagram of a mechanical temperature and pressure correction device showing a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional mechanical temperature and pressure correction device.

FIG. 4 is a sectional view taken along the line AA in FIG. 3;

FIG. 5 is a side view of a conventional cleaner.

[Explanation of symbols]

 Reference numerals 35, 52: rotating shaft 36: pressure correction disk 38: pressure correction ring 53: temperature correction disk 55: temperature correction ring 64: correction integration counter 70: cleaner 73: cleaner body 77: wiping member

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F030 CC13 CD15 CD17 CE14 CE16 CF20 2F031 AA08 AC10 AD01 AF04

Claims (3)

[Claims] 1. A disk which is rotatable, and which is rotated in conjunction with rotation from a gas meter for measuring a gas flow rate, and which is displaced in proportion to a pressure from a pressure sensor for sensing a pressure of the gas to be measured. A pressure compensation ring that moves in the radial direction of the plate and contacts the surface of the disk to transmit rotation in a stepless manner. A temperature correction ring in which the disk is moved in the radial direction by a displacement amount proportional to the temperature from the temperature sensor to be sensed and rotation is transmitted steplessly; and rotation of the temperature correction ring subjected to pressure correction and temperature correction. A correction integration counter for integrating and displaying the gas flow rate, and slidably provided in the vertical direction facing the surface of the disk, and contacting the surface of the disk by its own weight to clean the surface of the disk. Mechanical temperature pressure compensation apparatus characterized by comprising a cleaner, a having a wiping member having elasticity to ring the distal end portion. 2. A pressure correction disk which rotates in conjunction with rotation from a gas meter for measuring a gas flow rate, and a pressure from a pressure sensor which interlocks with the pressure correction disk and senses the pressure of the gas to be measured. A pressure compensating ring that moves in the radial direction of the pressure compensating disc by a proportional amount of displacement and is continuously variable; a temperature compensating disc that transmits rotation to a compensation accumulating counter that accumulates and displays the gas flow rate; The temperature compensating disk is rotated by interlocking with the rotation of the pressure compensating ring to transmit the rotation to the temperature compensating disk and to displace the temperature compensating disk by a displacement amount proportional to the temperature from the temperature sensor for sensing the temperature of the gas to be measured. A temperature correction ring that moves radially and is continuously variable; a pressure correction disk; and a temperature correction ring slidably provided in a vertical direction facing at least one surface of the temperature correction disk.
A mechanical temperature and pressure compensator, comprising: a cleaner having a resilient wiping member at a distal end for cleaning the surface of the disk by contacting the surface of the disk by its own weight. 3. The mechanical temperature and pressure compensator according to claim 1, wherein the wiping member is a sponge or a felt cloth.